| Summary: | Thesis (M.Eng.)--Memorial University of Newfoundland, 1998. Engineering and Applied Science Bibliography: leaves 140-143. This thesis deals with a comparative study of the features of constant frequency and variable frequency current control schemes for power factor correction in AC-DC converter circuits. -- Various current control schemes for achieving nearly unity power factor at the input and to minimize the total harmonic distortion (THD) are in use in various applications such as television, radio receivers, AC-motor drives, DC-motor drives and uninterruptible power supplies (UPS). -- Analytical models of Constant Frequency Continuous Current (CFCC), Constant Frequency Discontinuous Current (CFDC), Zero-Current Zero-Voltage Switching (ZCS-ZVS) and Variable Current Hysteresis Control (VCHC) are developed and used to evaluate the performance of the power factor correction circuit. The main features of these control schemes are highlighted and the performance characteristics are obtained through computer simulation for the same circuit conditions. Design examples of each control scheme, and power loss calculation associated with the active switching device are also provided. It is shown that active current waveshaping through constant and variable frequency control schemes posseses many attractive features.
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